Pyrex is a Python-like language for rapidly and easily writing python extension modules. It can be described as python with C data types. With Pyrex, one can produce Python-like code that runs as fast as in C, with easy access to C libraries and functions.

If you are looking for speed improvement, you may also want to consider other Python speedup solutions such as PyPy and weave. PyPy's spiritual predecessor, psyco, has been deprecated and is no longer actively maintained.

For accessing existing C libraries, the ctypes module is also available in Python 2.5 and above.